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CERCLA Removal Action – Deeter Foundry Specific Applicable SIN Numbers:
Deeter Foundry retained the services of Olsson Associates after being required by the U.S. Environmental Protection Agency (EPA) to complete an emergency removal action of lead-contaminated foundry sand at a construction company site in Lincoln, Nebraska. The construction company used the foundry sand as initial fill and had placed a two-to-three-foot layer of soil mixed with rock over the foundry sand as final cover. OA developed a sampling and analysis plan, site safety plan, and quality assurance documents in accordance with EPA requirements. OA also coordinated the activities with the Lincoln-Lancaster County Health Department and the Nebraska Department of Environmental Quality (NDEQ). Field activities included sediment characterization (onsite using X-ray fluorescence and an offsite laboratory), delineation of removal boundaries, foundry sand stabilization, and off-site disposal. The treated foundry sand was disposed as special waste in accordance with NDEQ Title 132 regulations. OA facilitated several meetings with the client and property owner. At the initial meetings, we discussed project details and obtained information from the property owner as to where exactly the foundry sand was buried. Later meetings provided briefings on project status. OA coordinated with the EPA and client on scope of work issues as they arose. One of the more significant issues involved the area of remediation that more than tripled in size from initial estimates. The client was satisfied with this project as the EPA released them from further requirements. They continue to consult OA for environmental issues. Groundwater Modeling and Petroleum Treatment Specific Applicable SIN Numbers:
The Nebraska Department of Environmental Quality required clean-up of free product from the groundwater. Clean-up activities at the site have been conducted in two phases. Initial remedial actions included designing a system to collect free-phase product and control plume migration. The second phase consisted of soil excavation. For several years, OA monitored the groundwater to establish baseline site conditions. To determine the feasibility of various clean-up methods, OA conducted pilot testing, including a pump test, injection test, and a soil vapor extraction test. We modeled a recovery trench system to determine its effectiveness in removing free-phase contamination. In addition, there were no surface water discharge options available; thus, groundwater injection was considered for disposal of treated groundwater. The model was used to simulate groundwater injection and to determine its feasibility. Based on the model, the trench and injection system was found to be capable of meeting project goals. We used a MT3D model to assess the designed system’s capability in controlling the dissolved contamination. A gravel-packed recovery trench system was designed and installed to capture and control the plume. The recovered groundwater was treated using air stripping and carbon absorption. The treated water was injected through a 300-foot-long horizontal well up-gradient of the plume. The system operated for two years, while an excavation plan was developed to remove the highly contaminated soils in the source areas. Due to the location of the plume, the excavation plan was carefully developed with input from the Village, owner, NDEQ, and several adjacent landowners that would be affected by the excavation. The client was satisfied with the work Olsson Associates performed and has used OA for these services since 1995. Sand Creek Watershed Environmental Restoration - Specific Applicable SIN Numbers:
The seven upstream structures are intended to provide localized flood protection and reduce sediment and nutrient loading. The Lake Wanahoo site will be an earthen embankment dam that will span Sand Creek to create a 639-acre lake, which will possess significant environmental, flood control, and recreational benefits. The entire site will consist of approximately 2,000 acres of restored wetland and prairie habitat that will eventually be administered as a State Recreational Area by the Nebraska Game and Parks Commission. Olsson Associates was retained to do planning work, including formulation of alternatives; screening of alternatives using economic analysis and methods designed to compare cost-benefits of non-monetary outputs; and preliminary design work, as well as to collect baseline data; analyze environmental, social, and economic impacts of the alternatives; and produce the integrated Feasibility Report and Environmental Impact Statement (EIS), a single document that met both Corps of Engineers planning and NEPA/404 requirements. Services included surveying, hydrologic studies, geotechnical studies, wetland delineations, habitat evaluations, threatened and endangered species surveys, and cultural resource investigations; coordination with government agencies, the public, and tribal authorities; preliminary designs; and presentations at public hearings. This project received the 2002 Outstanding Planning Achievement Award for the Omaha District U.S. Army Corps of Engineers. Murdock Phytoremediation Site Wetland Design – Specific Applicable SIN Numbers:
This project included the planning, design, and construction of a water quality wetland downstream of a phytoremediation site near Murdock, Nebraska. Argonne National Features were incorporated into the wetland design that would encourage volatilization of carbon tetrachloride during the non-growing season as well as phytovolatilization and rhizodegradation during the growing season. As with any constructed wetland, control of the hydrologic regime is an important consideration for water quality improvement, habitat development, and maintenance. The water level of this wetland is controlled by adjustable stop-logs mounted in a concrete outlet structure. Although typically wetland restoration sites are designed to safely pass 25-year storm events, this outlet structure was sized to safely pass a 100-year storm event. The site also takes advantage of enhanced wildlife habitat by incorporating an interpretive recreational trail that meanders around the wetland. The site has also been designed to be accessible for water quality monitoring, scientific investigations, and educational study. More can be learned about the Murdock phytoremediation project at http://www.anl.gov/ER/Research_Programs/AGEM/Highlights/Murdock.html |
Olsson Associates was retained by Dankert’s Inc., after petroleum contamination from 14 leaking underground storage tanks impacted groundwater within a one and one-half-block area. Contamination included both dissolved and free-phase petroleum product. The water table in this area fluctuates over 15 feet annually, and, at its highest levels, is as shallow as two feet below ground. Additionally, the uppermost water-bearing interval consists of low transmissivity clay and silt overlying the Ogallala Group. One of the Village’s main sanitary sewer lines and other utilities traversed the plume. In addition, one residential basement near the plume’s terminus was monitored for potential vapor migration.
The Sand Creek Watershed Environmental Restoration project is designed to restore habitat and improve water quality in the Sand Creek Watershed in Saunders County, Nebraska. This watershed is typical of many in the agricultural Great Plains, and is characterized by loss of wetlands and other natural habitats; stream channel instability; water quality problems, including high sediment and nutrient loads; and frequent flooding problems. The $31 million project includes three main components: seven upstream sediment/nutrient dams, bottomland wetland restoration sites, and a large wetland and lake complex, Lake Wanahoo.
Laboratories developed the phytoremediation site in order to mitigate carbon tetrachloride entering a tributary to Pawnee Creek from a contaminated groundwater plume. To complement the phytoremediation site, a water quality wetland was constructed that offers multiple benefits to watershed stakeholders. The wetland incorporated features that provided a “polishing stage” in the carbon tetrachloride remediation process while protecting adjacent properties from flooding and channel instability, enhancing wildlife habitat, and creating recreational and educational opportunities for the citizens of Murdock.